EP0876893B1 - Method for injection moulding of plastic articles - Google Patents

Description

The invention relates to a device for Injection molding of plastic parts, consisting of one of at least two molded parts, formed injection mold with at least an inlet opening for spray compound, wherein the molded parts have sealing edges that at closed injection mold close together fit or close to a counter surface of the rest each other molded part, whereby a workpiece in the injection mold, e.g. a sheet of glass that can be inserted to the or a border on the edge Plastic is injected, the Moldings have dividers that run towards each other and at closed injection mold to form sealing edges Face the workpiece so that a sealed recess for Injection molding of the skirt is formed, finally the sealing edges of the Molded parts thanks to spring-elastic elements formed and parallel to the closing direction of the Moldings of the injection mold adjustable are.

It is common in the prior art that the outer edge of the injection mold in the Partition plane has sealing edges, by means of which prevents the molding compound from the actual mold cavity of the Injection mold can leak. They are too Injection molds with so-called sliders known, also in the area of Slider sealing edges are provided to the escape of spray compound prevent.

Devices are also generic known, into which a workpiece, for example, a sheet of glass is to make a border on the edge Injection molded plastic.

Such Training is from DE 32, for example 16 063 C3 known and from the G 94 08 981.7 a mold for molding a Seal on a sheet of glass, the Forming tool from an upper and a Lower tool exists and in the respective Areas of the upper tool with at least provided with a movable insert is.

From EP A 0 401 091 is also a device for an injection mold known, with a workpiece in the Injection mold is insertable, at the Edging made of plastic is injected and that for injection molding the sealing edges provided through one in the designated chambers located, adjustable pressure fluid are formed and thus sealing against the Workpiece to be pressed.

DE 32 27 014 A1 is a Device for pressure spraying a Known edge protection made of plastic, being in the injection mold for example a plate made of wood-based materials inserted will and for sealing the mold space Plate towards sealing strips made of steel are provided in the mold halves are limitedly displaceable and under the action of an elastic pressing force stand.

Also from EP 0 081 671 Device for the encapsulation of the rotating Cut edges of wood-based panels known.

From the publications JP-A-57 193 334, JP-A-07 156 193, JP-A-03 292 120, DE-A-35 32 424, WO-A-87 04 973 and EP-A-0 127 546 are others Generic devices known.

With all such devices, it will considered a disadvantage that after a corresponding number of spray cycles Wear sealing edges and thus one elaborate post-processing of the molded parts and the like is required.

Based on this state of the art the invention has for its object a To create a generic device, which allows the Sealing edges in a simple way the function of the injection mold or the sealing edges according to their purpose train.

To solve this task, it is proposed that each resilient element by a Push belt is formed, the one Variety of essentially transverse to Longitudinal course of the closing direction of the Moldings adjustable sealing edge directed, immediately adjacent, has dimensionally stable rod elements, which in a Backing layer made of flexible material used or held by this, the carrier layer on which the sealing edge supporting molded part is fixed, and that the Distance between adjacent bar elements of the push link belt is so low that prevents the inflow of spray compound is.

It is advantageous that the resilient Elements by means of documents or by Adjusting means relative to the parting plane of the Molded part adjustable and lockable are.

This makes it simple possible, the sealing edges also partially in Subdivide areas, if in one Part of a wear of the sealing edge takes place in the areas on are heavily used. The other areas of the sealing edges can doing so in a conventional manner one-piece elements of the molded parts be trained.

The sealing edges are also the same completely parallel to the closing direction the molded parts of the injection mold adjustable so that when worn the sealing edges are adjusted can, so the injection mold continues for the production of corresponding parts can be used without being one requires great effort.

Under certain circumstances, that the documents are transferred between the Sealing edge and the molded part carrying it arranged spacer bars are formed.

Alternatively or additionally, too be provided that the documents by between the sealing edge and that it load-bearing molded part inserted Spacers are formed.

Furthermore, alternatively or additionally also be provided that the adjusting means through between the sealing edge and the it load-bearing molded part screwed Set screws are formed.

The viscosity of the spray compound is usually not so big that a Flow of spray compound into the gap between the neighboring finger-like Spring elements are to be expected. In each Case the gap can be made so small be an inflow of spray compound is prevented. Freezes during the spraying process the molding compound in the mold like this quickly that an inflow of No injection compound into the slots anyway is to be expected.

A particularly preferred training is seen in the fact that the sealing edges partially or completely parallel to Closing direction of the molded parts Injection mold are resilient.

When in the prior art from the DE 32 16 063 C3 known Injection molding device are already in Free space of the molded parts abutment used with the mold closed when molding the edge of a pane with plastic on both sides of the encapsulating discs tightly fitting touch. That limit the freedom Separators jump over the outer sides of the disc so that there is an annular gap on both sides of the disc arises. The one with a plastic too splashing edge of the disc lies outside the dividers. Since the distances of the Separators from the pane at the known injection mold are very small, becomes part of the spraying process displaced air into an air cushion compressed so it's inevitable there for a seal between the free spaces and comes to the abutments.

With this tried and tested version it turned out that the Not all abutments in practice Occurring cases are sometimes strong varying disc contours that in Are normally curved, sufficient to adjust. This then leads to the necessary clamping forces of the abutments often turn out too low. Another disadvantage is that the sealing effect of the between the Air pillow dividers in many Cases are not sufficient to penetrate of the plastic used for the encapsulation the disk edge is provided in the to prevent medium free spaces. By the training according to the invention can the injection molding device in constructed in a structurally simple manner be that reliable adjustment from sealing edges of the injection mold to everyone usual disc contours respectively Disc curvature occurs and that Leakage of plastic from the Enclosing the edges of the pane Injection mold recesses reliable is prevented.

This is generally advantageous training especially preferably provided if with a sprayer Injection molding the edge of a glass sheet or another workpiece entirely or partially extensive surround Plastic the molded parts of the injection mold Have free spaces that go from each other directional sealing edges are limited, against which the edge to be encapsulated the glass pane or the workpiece outside in an injection mold recess protrudes, and when to clamp the Glass pane or the workpiece at least on an outer surface of the glass pane or of the workpiece at least partially or fully circumferential springy flexible sealing edge is provided.

The seal in the area of the sealing webs takes place on the glass pane or on the Workpiece through a relatively narrow edge the resilient sealing edge, see above that an effective seal barrier between the inner freedom and the outer Form recesses are created. In particular when the sealing edge is made of rigid thermally highly resilient material, for example, metal, are in in practice, extremely long service life reached. In addition, the on its edge encapsulating disc or the like one versus the entire area of the Disk very small area sufficient firmly clamped. Because the sealing edge is springy compliant is sufficient Assured mobility so that when Closing the molded parts an automatic Adaptation to different Disc curvatures and contours. This will result in the risk of breaking panes strong during the production process diminishes and thus the economy noticeable in such mass production elevated.

Due to the training according to the invention processing even larger ones Curvature tolerances of the panes or Workpieces possible. The previously necessary Work to re-wash the sealing edges with different disc dimensions are reduced as much as Repair work. Overspray that due to leaks in the area of Sealing edges can be created largely avoided, so that a little rework required is. In addition, the springy compliant sealing edge arrangement the Clamping the glass pane or the like take place, so that possibly so far Usual positioning stops are not necessary can and also a rigid position of the Disc or the like during the Spraying process is guaranteed without that to do this, attacks or the like would be required. Such attacks lead in the state of the art sometimes Disc breakage, when e.g. the Disc not yet against the Positioning stop is created and Spray compound is injected, whereby by the injection pressure the disc against the Positioning stops is moved and the edge can be damaged. To avoid this, the Technology the complex front hemming of the disks, what is required by the training according to the invention can be omitted.

It is particularly preferably provided that both sides of the glass pane or the Workpiece between the corresponding Molding and the glass pane or the Workpiece a resilient Sealing edge, partially or completely all around, is arranged.

This is an even adjustment the resilient sealing edge to the Contours of the disc or the like possible on both sides.

There is an easy-to-use solution also in that with a square Glass pane or a square workpiece the resilient sealing edge Individual elements is formed, the Individual elements leave the corner areas free and rigid sealing edges in the corner areas in addition to the flexible sealing edges are provided on the molded parts.

Here, the resilient sealing edge can be formed from several individual elements, leaving the corner areas free and are formed by rigid sealing edges, that from the material of the molded parts consist.

Just like the one described at the beginning adjustable sealing edge arrangement can the resilient sealing edges in a simple way to make an adjustment for example by underlaying Spacer bars or set screws Tolerance compensation is made.

Furthermore, it is preferably provided that the edge or glass pane as orthogonal separating edge or cutting edge is designed without trimming.

Figur 1

eine Spritzgießvorrichtung im Querschnitt bei geschlossenen Formteilen;

Figur 2

einen Ausschnitt in vergrößerter Darstellung;

Figur 3

ein Formteil der Gießform in Ansicht;

Figur 4

eine Einzelheit in vergrößerter Darstellung;

Figur 5-7

weitere Einzelheiten in vergrößerter Darstellung;

Figur 8 und 9

eine weitere Einzelheit in der Ansicht gemäß Figur 5 und 7.

Schematic embodiments of the invention are shown in the drawing and described in more detail below.
It shows:

Figure 1

an injection molding device in cross section with closed moldings;

Figure 2

a detail in an enlarged view;

Figure 3

a molding of the mold in view;

Figure 4

a detail in an enlarged view;

Figure 5-7

further details in an enlarged view;

Figures 8 and 9

a further detail in the view according to Figures 5 and 7.

The embodiments according to FIGS. 5 to 9 are not part of the invention, in particular no embodiments of the invention.

In the drawing figure 1 is schematic a device for injection molding Plastic parts shown. it consists of an injection mold 1 with two molded parts 2.3 (mold halves in the exemplary embodiment). The injection mold 1 has at least one Inlet opening 14 for spray compound. The Moldings 2,3 have sealing edges that in the area of the closing surfaces 4.5 in generally without a liner Gasket pressed against each other. There is at least one of the two Closing surfaces 4 or 5 often with one molded sealing edge formed. The Mold halves 2,3 each have approximately in the Free spaces 6,7 in the mold as well a circumferential recess 8 on the the free spaces 6,7 by two Recess 8 delimiting, against each other directional, circumferential sealing webs 9 are limited. The spacing of the sealing webs 9 are designed so that between them a disc 10 is inserted tightly.

According to the invention, the sealing webs 9 Sealing edges on either only in Partial areas or even over their entire are adjustable. Training such a seal is shown in Figure 5 to 7 explained in more detail using an example. There is a sealing web sealing web 9 in the form of a rigid sealing edge above the disc 10 formed on the Disc 10 is present during the corresponding sealing web on the underside of the Washer 10 through a sealing edge 11 is formed, which is parallel to Closing direction of the molded parts 2,3 is adjustable. The sealing edge 11 is thereby by resilient elements 12 formed, for example, by Documents or means of positioning relative to Parting plane of the molded part 3 adjustable and are noticeable. According to the The embodiment according to FIG. 5 is Underlay between the sealing edge 11 and the molded part 3 inserted spacer wedges 13 formed, so that rigid, different sealing contours can be set respectively a stronger spring force can be set can. In the embodiment according to FIG. 6 is the actuating means by a between the Sealing edge 11 and the one carrying it Molding 3 screwed set screw 15 educated. This can also cause a rigid Sealing contour in adaptation to the target shape getting produced. According to the training for example, according to Figure 2, the later described in more detail, it can spring elastic element by a Push link belt 16 be formed, which in essentially transverse to the longitudinal course of the Sealing edge directed dimensionally rigid Bar elements 17, which in a Backing layer 18 made of flexible material, for example rubber used by these are held, the Carrier layer 18 on which the sealing edge supporting molded part 2 or 3 is fixed. For example in the embodiment according to Figure 5 to 7 is the resilient Element 12 formed by a leaf spring, the base 19 on which the sealing edge 11 load-bearing molding, such as the Molding 3, is fixed and from its base 19 finger-like isolated spring elements 12 protrude in the same direction. How 5 and 6 in particular, are the finger-like elements 12 in Longitudinal section approximately L-shaped, one of the L-shaped ridges in the base 19 the leaf spring merges and the other Bridge of the L-shape to the counter surface of the projecting molded part 2 protrudes and on this or in the exemplary embodiment on the Contact surface of the in between Workpiece (disc 10).

The distance between the neighboring ones Rod element 17 of the push link belt 16 or the finger-like spring elements 12 of the Leaf spring is so low that a Influence of spray compound excluded is.

While in the embodiment for example according to FIGS. 5 to 7 resilient element 12 is fixed, thus when the disc 10 is placed for example, cannot spring or the Travel is at least rigidly limited in the embodiment, for example Figure 8 and 9 and also in training according to Figures 2 and 4, the sealing edge resilient yielding. The support themselves resilient fingers (resilient elements 12) or the resilient Rod elements 17 on the disc 10 resilient compliant, so that the so formed Sealing edge of the corrugation or contour or Curvature of the disc 10 can follow and nevertheless a dense plant is reached. As can be seen from FIG. 3 in the case of an angular shape of the glass pane 10 or a corresponding angular workpiece through the resilient sealing edge 11 Individual elements that are formed Leave corner areas, whereby in the Corner areas 20 rigid sealing edges in Complementing the flexible sealing edges (11) on the corresponding molded part 2 or 3 are provided.

In the embodiment according to Figures 5 and Figure 8 are additional Positioning means 21 provided in a starting position in the Drawing figures is shown in which the molded parts 2, 3 of the injection mold 1 Closing the shape are approximated and the sealing edges 9 and 11 respectively the glass pane 10 or the workpiece apply, distance from the glass pane 10 or have the workpiece.

This training will improve a secure, yet soft holder of the Glass pane 10 in the mold 1 guaranteed, due to this Arrangement of the peripheral edge of the Glass panel 10, for example, not trimmed must be, but it can only be through be a separating cut, the orthogonal to the area extension of the Glass pane 10 runs. By the Positioning means 21 ensures that the edge of the glass sheet 10 not against stationary stops or the like pressed and by trimming the Glass pane 10 no longer required is, the end product can be cheaper are manufactured.

Claims (10)

1. Device for injection moulding of plastic parts comprising an injection mould (1) formed from at least two mouldings (2, 3) with at least one inlet opening (14) for the injection moulding compound, where the mouldings (2, 3) have sealing edges which when the injection mould (1) is closed lie tightly against each other or in each case against a counter-surface of the other mould part (2, 3), where further in the injection mould (1) can be placed a workpiece e.g. a glass pane (10) on the edge of which is moulded a border of plastic, where the mouldings (2, 3) have separating webs which run towards each other and when the injection moulding (1) Is closed lie tightly on the surface of the workpiece forming sealing edges (11) so that a sealed recess (8) is formed for injection moulding of the border, where finally the sealing edges (11) of the mouldings (2, 3) are formed by spring elastic elements and are adjustable parallel to the closing direction of the mouldings (2, 3) of the injection mould, characterised in that each spring elastic element Is formed by a thrust link conveyor (16) which has a multiplicity of directly adjacent, dimensionally rigid rod elements (17) directed essentially transverse to the longitudinal path of the sealing edges (11) adjustable to the closing direction of the mouldings (2, 3), said rod elements being inserted or held by a carrier layer (18) of flexible material, where the carrier layer (18) is fixed to the moulding (2 or 3) carrying the sealing edge (11), and that the distance between two adjacent rod elements (17) of the thrust link conveyor (16) is so slight that the penetration of injection moulding compound is prevented.
2. Device according to claim 1, characterised in that the spring elastic elements (12) can be adjusted and defined by means of shims or adjustment means relative to the parting plane of the mouldings (2 or 3).
3. Device according to claim 1 or 2, characterised in that the shims are formed by spacer strips arranged between the sealing edge (11) and the moulding (2 or 3) carrying this.
4. Device according to claim 1 or 2, characterised in that the shims are formed by spacer wedges (13) pushed between the sealing edge (11) and the moulding (2 or 3) carrying this.
5. Device according to claim 2, characterised in that the adjustment means are formed by setscrews (15) screwed between the sealing edge (11) and the moulding (2 or 3) carrying this.
6. Device according to any of claims 1 to 5, characterised in that the sealing edges (11) are sprung flexible partially or completely parallel to the closing direction of the mouldings (2, 3) of the Injection moulding (1).
7. Device according to claim 6, characterised in that for an injection device for moulding of a border of plastic fully or partly surrounding the edge of a workpiece e.g. a glass pane (10), the mouldings (2, 3) of the injection mould (1) have spaces (6, 7) limited by sealing edges (11) directed towards each other, opposite which the edge of the workpiece to be overmoulded protrudes outwards into a recess (8) in the injection mould and that to clamp the workpiece, at least one sprung flexible sealing edge (11) is provided at least on one outer surface of the workpiece and surrounding this partly or completely.
8. Device according to claim 7, characterised in that on both sides of the workplece between the corresponding moulding (2 or 3) and the workpiece is arranged a sprung flexible sealing edge (11) surrounding this partly or completely.
9. Device according to one of claims 7 or 8, characterised in that for an angular workpiece e.g. an angular glass pane (10), the sprung flexible sealing edge (11) is formed of individual elements, where the individual elements leave the comer areas (20) free and in the comer areas are provided rigid sealing edges to supplement the flexible sealing edges (11) on the mouldings (2 or 3).
10. Device according to any of claims 1 to 9, characterised in that the edge of the workpiece is formed as orthogonal parting edge or cut edge without trimming.

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